1. Field of the Invention
The present invention relates to a simulation method and apparatus of jaw movement. More particularly, the present invention relates to a simulation method of jaw movement and an apparatus therefor that can be used for designing a dental prosthesis or the like with a computer.
2. Related Background Art
In recent years there are proposed methods for designing the dental prosthesis by CAD/CAM or the like, i.e., by using a computer. This method is arranged to measure a configuration of a dentition of jaw including a portion on which a prosthesis is to be mounted and to design a configuration of the prosthesis on the computer, based on the measurement data. In the case of such designing of prosthesis, it is the simplest way to design the prosthesis (crown, bridge, or the like) in consideration of the relation with adjacent and pairing teeth in the occlusal relation at the intercuspal position (centric occlusal position). This method, however, could cause a feeling of disorder during mastication, because it excludes consideration on a change in the relative positional relation between jaw dentitions under masticating motion.
In order to overcome such a problem, it is desired to simulate motion of jaw, use the simulation result for designing, and design the prosthesis in consideration of the motion of jaw. For this purpose, a demand exists for a simulation method as accurate and easy as possible.
Under such circumstances many attempts have been made heretofore to achieve simulation of jaw motion. Examples of such simulation include a method for capturing a three-dimensional configuration of dentition into the computer, giving quantities of movement step by step under conditions considered by a human, and continuously moving the dentitions by connecting the quantities of motion, a method of line representation for connecting the motion data step from step, a method without use of computer, for mounting a gypsum cast on an occluding device and observing motion thereof on the occluding device, and so on. However, these conventional simulation methods required a lot of labor and time for data input and execution of simulation, which was a problem for many of them in being put into practical use. In addition, the accuracy and process time thereof were not satisfactory.